Records 22 papers presented at a meeting concerned with the design of prospective studies to investigate the role of diet and hormones in the etiology of cancer. The objective of the meeting was to identify methodological differences and common elements in both on-going and planned studies in order to facilitate the consolidation of data, communicate practical lessons about the advantages and pitfalls of different methodological approaches, and avoid duplication of efforts. Papers are presented in four main parts. The first describes on-going or planned prospective studies on diet and cancer at centres in the USA, Holland, Italy, France, Finland, Sweden, Denmark, and Poland. Papers in the second section, devoted to dietary assessment methods for epidemiological studies, communicate experiences in the use of dietary questionnaires and in methods for attenuating the problem of measurement error in nutritional epidemiology. Methodological problems in the use of biochemical, anthropometric and other measures of diet and nutritional status are considered in the third section. The book concludes with papers describing four prospective studies designed to determine the link between endogenous and exogenous hormones and cancers of the breast and female reproductive organs.